Machine Machine Type Communication (MTC) is currently an important focus for research of fifth generation (5G) mobile communication technologies; it is also an important application area for the future of wireless communication. In MTC topic, a research sub-topic of Narrow Band-Internet of thing (NB-IOT) has been proposed for characters of terminal—such as low cost, low power consumption, low mobility, and low throughput, etc; that is, to provide within the frequency band of 200 kHz low-throughput wireless communication services for NB-IoT low-cost user equipment (UE).
In the original Long Term Evolution (LTE) air interface initial establishment process, terminals use competitive mechanisms, and transmit a preamble before initiating a random access (RA) response window in the position of the 3rd subframe after the last subframe of the preamble transmission, whereupon the terminal waits to receive the random access response (RAR) message. The length of the RA response window is configured by system messaging; the largest length is 10 wireless subframes (i.e., 1 wireless frame). Terminals use Random Access-Radio Network Temporary Identity (RA-RNTI) to demodulate the Physical Downlink Control Channel (PDCCH), and then demodulate the Physical Downlink Shared Channel (PDSCH) to obtain the Medium Access Control (MAC) Protocol Data Unit (PDU) containing its RAR. The time frequency position of the preamble determines the value of the RA-RNTI; the base station and the terminal respectively calculate an identical RA-RNTI value based on the preamble time-frequency position. Within the relevant standard, the formula for calculating RA-RNTI is as follows:RA-RNTI=1+t_ id+10×f_id, 
Wherein, t_id indicates the sequence number for the initial subframe of the preamble transmission (i.e., the first subframe), and the value range is [1, 10), that is, 0≤t_id<10; f_id is the frequency domain position of the Physical Random Access Channel (PRACH) within the subframe, in ascending order, the value range is [0, 6), that is, 0≤f_id<6. According to the above formula, the value range for RA-RNTI is [1, 60].
For the Frequency Division Duplexing (FDD) system, f_id is always equal to 0, and the above formula can be simplified as:RA-RNTI=1+t_id, 
Wherein, t_id indicates the sequence number of the first subframe of the terminal preamble transmission.
Based on the preceding content, we see: (1) if two terminals transmit the preamble in the same subframe of the same radio frame, their RA response windows overlap, the RA-RNTI of the RAR transmitted by the base station to scramble the PDCCH is also the same, and can only be processed with subsequent interference resolution; (2) if two terminals transmit the preamble in the same subframe of different radio frames, although the RA-RNTI of the RAR transmitted by the base station to scramble the PDCCH is the same, the RA response windows of the RAR received by the two terminals cannot overlap because the RA response windows will not be longer than 1 wireless subframe, and RA response window separation can be used to avoid interference; (3) If the two terminals transmit the preamble in different subframes of different radio frames, different RA-RNTI can be calculated to avoid interference.
In summary, based on the value ranges of RA response windows of relevant standards, the RA-RNTI calculation only needs to reflect the difference between varying initial subframes of preamble transmissions.
But for MTC and NB-IoT communication scenarios, the ability of low-cost terminals to transmit and receive information is limited, or there is poor coverage, so the related research has introduced repetitive functions during uplink transmission and downlink transmission; that is, no matter if the terminal is transmitting uplink messages or the base station is transmitting downlink messages, a certain number of repeat transmissions is enacted to ensure reception. Correspondingly, the required time for the terminal to receive downlink information or the base station to receive uplink information could be extended; therefore, the value range for RA response windows in the related research has been expanded, with the largest being 400 subframes (i.e., 40 radio frames).
The related research has also introduced the concept of coverage rankings to reflect the difference between coverage areas and scenarios. It can be considered that the uplink channels for terminals that are located in the same coverage rankings can use the same repeat factors, and the length of the RA response window can also be the same.
To summarize the preceding analysis, we see that for terminals that transmit the preamble in the same subframe of different radio frames, RA response windows could overlap because the length of RA response windows can exceed 1 radio frame after extension. FIG. 1 is an illustration of the RA response window overlap of two terminals caused by the extension of the RA response window. Within FIG. 1, the subframe with grid markings is the initial subframe position for the preamble transmission; the subframe with slash markings is the RA response window position. However, based on the existing RA-RNTI calculation formula, the RA-RNTI of the two terminals expressed in FIG. 1 is the same; on the one hand, the two terminals may need to demodulate the PDCCH twice within the overlapping RA response window, which will increase power consumption; on the other hand, the two terminals could use the same preamble sequence at the exact same time, and the content of their RAR will be the same, which would require a subsequent interference resolution process, wherein at least one terminal will have a reception failure, which is equivalent to additional interference.